Regulator



Feb. 7, 1928.

C. H. SMOOT REGULATOR Filed March 7. 1927 llllllllllllll INVENTOR (gyrij///WOOT' BY vn ATTORNEYS Patented, Fa.. 7, 1928.?

CHARLES H. SHOOT, 0F MAYPIJEWOD, NEW JERSEY.

REGULATOR.

Application led March 7, 1927. Serial N0. 173,226.

My invention is concerned with a novel regulator so constructed as toavoid huntlng without loss of sensitiveness or power.

My regulator is of the type whereln an unbalance between. aregulating/force or forces and avforce'varying with a function of theelement controlled effects the regulation of an element through anintermediate power means. My invention comprises electrical power meansactuated upon an unbalance of regulating and regulated forces foreffecting the control of the element and for preventing hunting of theregulator.

ForV an understanding of my invention, reference should be had to theaccompanying drawings of which Fig. 1 illustrates one embodiment of myregulator as applied to the control of a fluid pressure, and i Fig. 2illustrates an alternative arrangement of a part of the apparatus shownin Fig. 1.

Referring now to Fig. l, a damper 1' effects the control of the ow offluid through a conduit 2. The damper is oper-l ated to maintain aconstant fluid pressure atsome point in the fiow and is adjusted toOtheposition corresponding to the desired pressure by a reversible electricmotor 3 which turns the damper in either direction by means of rack 4and worm gear 5 mounted on the shaft 6 of the motor. One terminal of themotor 3 is connected by means of a lead wire 7 with a power circuit at8. The other terminalsofthe motor lead to contacts 9 and 10 arranged oneither side of a contact 11 carriedby a pivoted lever 13 and connectedthrough lead wire 12 to the other side of the power circuit at 8. Thelever 13 carries an adjustable weight 14 tending to turn the lever in acounter clockwise direction. Opposed to the turning moment offered bythe weight 14 to the lever 13 is a moment duc to th pressure of thefluid in the conduit 2 acting through a pressure bell 15 attached to thelever 13 and partially submerged in liquid, the space enclosedbetweenthe bell and the liquid being in communication with the conduit 2through pipe 16.

The apparatus so far described would operate to regulate the fiuid inthe conduit 2 for constant pressure, but only with continual hunting ofthe damper. If the pressure of the uid rises to a value greater than y28is screwed over the that for which the re ulator is adjusted, thepressure within the gell 15 overpowers the effect of the weight 14 andtips the lever, thereby closing contacts 9 and 11 and energizmg themotor 3 to close the damper 1. As long as the pressure within the bellis greater than that desired the motor 3 will continue to close thedamper. By the time the reduction in pressure caused by the closlng ofthe damper is felt at the lever the damper has been still furtherclosed. This results in a too low value of the pressure in the bell andan energizing of the motor 3 b contacts 10 and 11 driving the motor inthe reverse direction and to a position too far open.

The apparatus now to be described prevents this oscillation of thedamper. A rod 17 1s shdably mounted in fixed bearings 18 and is providedend in which the head 19 of a second rod 20 i s free to turn. The rod 17carries projections 21v to which are attached springs 22. The springs 22are fastened to the end of the lever 13, the arrangement being such thatwith the normal position of the rod 17 and neutral position of the lever13 the springs 22 exert no force upon the lever 13. The rod 17 carries acontact arm 23 connected through lead wire 24 with the power circuit at8 and arranged to travel over fixed contacts 2,5 and 26 with upward anddownward movement respectively of the rod 17. The rod 20 is threadedthroughout its lower half and provided with longitudinal slots 27.a1ongits upper half. A member the rod 2O and is supported in a fixed bearing29 in which it is :tree to turn but not to travel vertically. A gear 30forming a part of the member 28 meshes with a gear 3l on the shaft of areversible electric motor 32, which motor is connected in parallel withthreaded portion ofwith a socket in its lower the motor 3 and istherefore actuated wheni ever the motor 3 is actuated. The up er half ofthe rod 2O passes through a member 33 to which it is keyed by means oflongitu' dinal ridges on the inner side of the member which fit into theslots 27. The member 33 is mounted inl fixed bearings 34 in which it isfree to turn but not to move vertically. A gear 35 forms a part of themember 33 and meshes with a gear 36 driven by a third reversibleelectric motor 37, one terminal of which is connected through lead wire38 with the power circuit'at 8 and the other termlnals vof which areconnected tothe stationary contacts 25 and 26.

The arrangement ot' the motors 32 and 37 with the rod 20 is such thateither motor can raise or lower the rods, and if both motors areoperating at the same time the travel of the rod will be either the sumor diiference of thetravels that would be caused by either motor alone,depending upon whether the motors are aiding or opposing each other.yits shown, the gear 30 has a smaller\ diameter than the gear 35 andcorrespondingly fewer teeth with the result that with equal speeds ofthe motors, the rod will travel more rapidly with the motor 32 than withthe motor 37.

The operation of the entire apparatus disclosed in Fig. 1 is as follows:`With aV steady flow through the conduit- 2 and a pressure in the bell15 just suiicient to maintain the lever in the neutral position, themotors 3, 32 and 37 will not be operating because the contact 11 willnot be touching either of thecontacts 9 or 10 and the contact 23 willnot be touching either of the contacts 25 or 26. Assume now that thepressure in the conduit 2 and therefore in the bell 15 rises. Thiscauses the contacts 11 and 9 to close and the motors 3 and 32 to operatesimultaneously, the one to close the damper, the other to raise the rods2U and 17. The raising of the rods 20 and 17 applies a resilient forceto the lever 13 through the compression of the lower spring 22 and thetension of the upper spring tending to open the contacts 11 and 9. Itthe increase in pressure in bell 15 was very great the motor 32 may haveto raise the rods 17 and 20 very considerably before exerting enoughforce upon the lever to break the contacts and so to stop both motors 3and 32. As soon as the rod 17 has been raised 1sufficiently to close thecontacts 23 and 25 the motor 37 starts to turn the member 33 in adirection to lower the rods 20v and 17. While both the motors operate atonce the motor 37 acts to slow up the travel of the rods, but as soon asthe force exerted by the springs 22 is sufficient to break theelectrical circuit through the lever, the rod begins to be slowlylowered by the motor 37 which thus gradually releases the force upon thelever due to the springs 22. The speeds of the motors or the size of thegears are preferably so chosen that the tlme taken for a change in thesetting of the damper 1 to be felt as a pressure change in the bell 15will correspond to that taken by the motor 37 to release the tension ofthe springs upon the lever 13.

With a decrease in pressure within the bell 15 the operation is ofcourse just the reverse of that described above. The contacts 1() and 11close energizing motors 3 and. 32, causing them to operate in thereverse dlrection to that when contacts 9 and 11 are closed andresulting in an opening ot the damper and a lowering of the rods. Thetension of the springs upon the lever is thus increased until it becomessufficient to open the contacts and to stop the motors. The motor 37actuated when the rod was lowered gradually returns the apparatus to theneutral position. Y

It the` damper has not been moved far enough by the time the motors' 3and 32 are stopped, then these motors will again be energized as soon asthe tension of the spring 22 has been sutiiciently reduced.

Fig. 2 illustrates a slightly dierent arrangement of lever, springs andcontacts. In this arrangement the springs 22 are not carried by the rod17 but are xed at their ends to stationary members 21', and the contacts9 and 10 are carried by the rod 17 instead of being fixed.

The operation ot' each arrangement is the same in that aclosing of thecontacts 11 and 9 or 11 and 1() results in a movement of the rod tendingto open` the contacts and to increase the tension of the springs uponthe lever. In the embodiment of Fig. 1 this is accomplished by an upwardmovement of the rod when the .contacts 9 and-11 are closed and by adownward movement of the rod when the contacts 10 and 11 are closed. InFig. 2 this vis accomplished by just the reverse movement of the rod 17,that is, a downward movement when the contacts 9 and 11 close and anupward movement when the contacts 10 and 11 close. In each arrangementthe closing of the contacts 23 and 25 or 23 and 26 results in a movementof the rod 17 in a direction to return it to the position from which ithas been moved.

I have now illustrated' onel embodiment ot' my invention and analternative arrangement of a part thereof. For convenience I have shownmy new regulator arranged to maintain constant the pressure of. a i'luidby the control of a damper. Obviously my in vention is not concernedwith the particular element controlled nor with the controlling force orforces which in' the particular case illustrated was a constant, beingthe value introduced by the position of the weight 1l upon the lever.Obviously this weight can be replaced with any desired fixed or varyingforce or forces without affecting my inventi'on. The particular 'meansherein shown for acting on the lever with a force varying as a functionof the element controlled is et' course immaterial, as any desired meansmay' be used.

Although I have shown the damper 1 and member 23 driven by Separatemotors, it obviously would not change the operation ot' my regulator ifboth ot these elements were driven by the same motor.

Two motors, however,

step is not sufficient it makes a further corupon the rection. Thelength of any step depends actual magnitude of the change in the elementand also upon duration of this change. A momentary increase or decreasein pressure, no matter how large, results in a very small movement ofthe damper and an immediate return to t-he original setting while alarge permanent change results in a n large movement of the damperbefore the Y and itself, and additional motor is stopped.

Obviously many substitutions and rearrangements of parts may be madewithout departing from the scope of my invention and parts of myapparatus may be advantageously employed without the corresponding useof other parts.

I claim:

l. In a regulating apparat-us of the type wherein an unbalance between aregulating force and a force varying as a function of the elementcontrolled effects the control of an element through auxiliaryelectrical power means, the improvement consisting in electrical meansactuated simultaneously with said power` means, for creating. agradually 1n creasing resilient force tending to stop both said powermeans and itself from functioning 4and additional electrical meansactuated when said resilient force reaches a definite value tending toreduce said force.

2. In a regulator of the type wherein an imbalance between a regulatedforce and a force varying as a function of the element controlledeffects the control of an element through auxiliary power means,l theimprovement consisting in electrical means Yactuated simultaneously withsaid power means for creitin a gradually increasing resilient forcetending to prevent the continued operation of both said power meansslower acting means tending to reduce and remove said resilient. force.

3. In a regulator of the type in which a regulating force opposes aforce which is a function of the regulated element, the combinationcomprising a reversing switch, the movable member of which is subjectedto said opposing forces and is 'normally acted upon in open position byequal opposing resilient forces, electric means actuated by closure ofsaid switch upon an unbalance of Atending to the forces acting upon saidmovable member, and operating to produce a regulating effect and tocause an unbalance of said resilient forces progressively increasinguntil suliicient to open said switch, andv other electric means broughtinto operation at a given vunbalance of to restore the normal balancethereof.

4. In a regulating apparatus the combination of a controlling means, amovable member acted upon by a regulating force and by a force varyingas a function of the element to be controlled, an electric motor foroperating said controlling means, means for driving said motor in onedirection with a' displacement of said member in one direction and forreversing said motor with a displacement of said member in the otherdirection, springs tending to hold said member in a neutral position,means for increasing continuously the force exerted on said member bysaid springs during continued operation of said motor, other meansoperating to return the force of said springs to zero and started intooperation when the force of said springs has reached a predeterminedvalue.

5..In` a regulator of the type wherein a regulating force opposes aforce which is a function of the regulated element, the combinationcomprising a reversing switch, theA movable member of which is subjectedto said opposing forces and -is maintained in open position by a balancethereof, a second movable member, electric means actuated by closure ofsaid switch under an unbalance of said forces, and operating to effectthe regulation and to move said second member,

the resilient forces and acting I means for creating a force increasingwith the displacement of said second member and reopen the switclnandlmeans, actuated v upon a definite displacement of said second membertending to return it to its original position and tending likewise toreduce and remove said last mentioned force.

6. In a regulator of the type wherein an unbalance betweenga regulatingforce and a regulated force varying as a function of theelement'controlled effects the control of an element throughintermediate powermeans,

the improvement'. consisting in a longitudinally movablemember 'andelectric means including at least one reversible electric motor -formoving said member andfor effecting the regulation of the element, meansfor actuating said motor upon an imbalance of regulating and regulatedforces, means carried by said member tending upon continued movementthereof to stop the operation of said electric means, another reversibleelectric motor for returning said member to its original position andmeans carried by said member for actuating said last named motor.

7. ,Apparatus as in claim wherein said longitudinally movable memberconsists of tW o parts', one carrying the means for actuating saidsecond motor and being adapted to be moved vertically by the other partbut tuatediby the closure of said switch for efectingl`v` the regulationand for creating a force'.increasing with the duration of the closureo:t tlre switch and acting upon said member in a direction to open theswitch, sloweracting apparatus tending to relieve said member of saidlast mentioned force, means for bringing said apparatus into operationafter said switch has been closed for a definite time, and forcontinuing it in operation until said member is relieved of said lastmentioned force.

In testimony whereof, I have signedrhy name to this specification.

CHARLES H. sMooT.

